SAN FRANCISCO (Reuters) - New Yahoo Inc YHOO.O CEO Marissa Mayer laid out broad goals for the Internet giant in her first companywide address Tuesday, and received an enthusiastic reception from a workforce that has faced years of uncertainty and management turmoil.

Mayer mainly sketched broad visions rather than concrete details for her turnaround strategy, according to several people familiar with what was said in the tightly controlled meeting.

But her personal credibility as a long-time senior Google Inc (GOOG.O) executive, combined with some recent morale-boosting moves such as providing new iPhones and free food for employees, have had a dramatic and positive impact on the "vibe" at the company, one of the people said.

Speaking at Yahoo's Sunnyvale, California headquarters, Mayer stressed the importance of personalizing Yahoo's Web services and adapting the company's products to mobile devices, AllThingsD reported. Although her speech touched on frequently mentioned industry themes, Mayer's delivery nonetheless won spontaneous applause from the workforce, according to a second person with knowledge of the company meeting.

"It was some of the same types of lines that had been said before, but people believe it now," said the person, who declined to be identified because the information is private.

After a steady stream of occasionally embarrassing reports, Yahoo in recent months has clamped down firmly on leaks to the press. Attendees at Tuesday's assembly were instructed to shut their laptops during Mayer's address.

Yahoo declined repeated requests for comment.

Mayer first presented her strategy to Yahoo's board in meetings last week, outlining plans to bring back advertisers and expand the company's user base, said a third source, who declined to be identified because the information was not public.

Yahoo also announced that it appointed as its new chief financial officer Ken Goldman, formerly CFO at cybersecurity software firm Fortinet (FTNT.O).

The appointment comes two months after Yahoo's board tapped Mayer to restore a household Internet name overshadowed by rivals like Facebook Inc (FB.O) and Google in recent years.

Yahoo remains one of the world's most popular websites, with more than 700 million monthly visitors who use products like its email service and read its news pages, according to the company. But Yahoo's revenue has stagnated as online display advertising prices have fallen and as it faces competition from Facebook and Google.

Mayer, Yahoo's third CEO in about a year, arrived after a tumultuous period in the company in which former CEO Scott Thompson resigned after less than 6 months on the job over a controversy over his academic credentials. Yahoo co-founder Jerry Yang had also stepped down as CEO, and an internal reorganization eliminated thousands of jobs.

Mayer's latest hire, Goldman, replaces Tim Morse, who served last year as interim Yahoo CEO while the company underwent another episode of leadership turmoil.

BOOST MORALE, SCANT DETAILS

Since taking the helm, Mayer has sought to boost morale at the nearly two-decade-old Internet company, eliminating corporate bureaucracy and introducing perks such as free cafeteria food and state-of-the-art smartphones for employees that are standard fare at other Silicon Valley Web companies.

But Mayer has so far offered scant details about her plan to revive revenue growth and to expand its audience - a challenge that has frustrated a string of her predecessors as well as countless shareholders.

Many analysts and investors believe Mayer will renew Yahoo's focus on Web technology and products rather than beefing up online content, as appeared to be the mission during interim CEO Ross Levinsohn's brief tenure.

That has raised concerns among some investors that Mayer will embark on an expensive acquisition spree.

Mayer assuaged some of those fears last week when Yahoo closed the sale of half of its stake in Chinese Internet company Alibaba Group. Yahoo said it would give shareholders $3 billion of the deal's $4.3 billion in after-tax proceeds.